The most suitable stocks recommended for Rubber stamps are primarily uncoated stocks. Uncoated stocks have no coating on the paper, making the paper feel natural, porous which makes it very absorbent to the stamp inks. Artwork stamped on the uncoated paper will be softer and less crisp.
15pt Brown Kraft
18pt Brown Kraft
You can also use the stamps on Matte coated card stock, however these will require several minutes drying time.